Process of treating oil and reagents



l No Drawing.

Patented June 21, 1932 ATENT GEORGE HENRY :ennnnss, or coLonAno, TEXAsQAssIGNOR T COL-TEX REFINING COMPANY, or COLORADO, TEXAS, AcoRronA'rIoN or DELAWARE rnoonss or TREA I G orni ivn REAGENTS This invention relates to the treatment of hydrocarbon oil and particularlypetroleum distillates whereby such oil may be sweetened and substantially freed of sulfur compounds which ordinarily may be of a corrosive nature and impart an objectionable odor to the oil-..

The invention also relates to a method of treating certain reagents and to a method of reconditioning sludges. obtained during treatment of hydrocarbon oils for the purposes of sweetening and substantially desulfurizing said oils.

In general it may be said that this inven tion is an improvement over the so-called doctor sweetened by agitation with solutions containing litharge (lead monoxide) dissolved in an excess of alkali, followed by an. application of free sulfur to facilitate the removal of oil soluble reaction products.

Furthermore, the invention pertains to a method of utilizing sludges resulting from the so-called doctor treatment whereby a great saving sweetening or refining operation may be carried out much more rapidly, thoroughly and economically. a i

An object of this invention is to provide a method forsweetening and refining hydrocarbon oils by which the consumption agents maybe materially reduced;

Another object is to provide a method for repeatedly regenerating a treating medium in the refining and sweetening of hydrocarbon oil.

Another object is to provide a treating medium for oil which may be efficiently removed from the treated oil without leaving any substantial portion of either the medium itself or objectionable reaction products in the treated oil.

A still further obgect is to provide a method of using lead sul sweeteningof petroleum distillates.

t 1 whereby losses of oil caused by entrainment in the treating medium are eliminated.

A sti'llfurther object of thisinvention is treatment in which oils arede in the treating and Another object is to provide a method of treating and sweetening hydrocarbon oils.

Application filed December12, 1928. Serial No. 325,659.

fining petroleum distillates by means of which such petroleum distillates may be sub stantially freed of sulfur compounds in an economical and rapid manner.

Other objects, advantagesand uses of this invention will be apparent from the following' detailed description of one preferred method of treating oils and of regenerating the treating medium.

In refining petroleum distillates of the naphtha, gasoline or kerosene type, the use of the so-called doctor treatment has often been resorted to particularly on what is known as sour oil so as to produce an oil having the greater portion of-the sulfur containing constituents removed therefrom and to produce a sweet product as evidenced by a negative doctor test. In carrying out the customary doctor treatment the oils are intimately mixed with a sodium plumbite solution such as is produced when litharge is dissolved in a solution of an alkaline hydroxide, customarily sodium hydroxide. The chemical reaction involved in preparing this treating medium is apparently the following .By adding the above solution to an oil, a considerable proportion of the impurities are precipitated in the form of a sludge but certain oil soluble lead-compounds are formed which may remain in solution in the oil. In practicallyall cases it is necessary to remove such on soluble compounds, and this is accomplished by adding free sulfur to the oil so as to precipitate the oil soluble impurities in the form of lead sulfide or other sulfides. This reaction using a typical mercaptan of a type which is ordinarily removed, for purposes of illustration may be expressed as folows:

2C H SH Na PbO S i C H 8 PbS +2NaOH Obviously other mercaptans. of complicated structure would reflect a more intricate equation but the above expressed action apparently occurs in all events, the oil being sweetened by chemical changes in the sour constituents leavingthe treating agent in the I extremely flocculent and carries with it a considerable proportion of the oil. .It. is ex,-

tremely difficult to separate such entrained oil'from the sulfide sludge"by'ordinary-set tling methods. Furthermore "even if the method is carefully regulated, the. cost of-reagents is relatively high and large quantities of litharge, often exceeding QIIBQPQHIldgPQI" gallon of treated oil, have to be used.

The sulfidesludge, including lead sulfide, caustic solution,-etc., is usually discarded'although some attempts have been mad'e'ito treat it for the recovery of lithargeforpurposes of re-using the'same in the-"treating process. The recovery of'litharge-from: lead sulfide sludge, while feasible in the laboratory sense andon a very small: scale includes complicated steps of decomposition by means of acids orcalcining which makethe process commercially unattractive and unused at the present time.

It has been found that the above described lead sulfide sludge as produced in a treating process of the type described hereinabove may be regenerated very readilyand reused repeatedly for treating oils, provided said regeneration is carried out "in accordan'ee with the process as hereinafter described. In

view of the factthat thesludge-maybeused repeatedly as the source-of treating agent, the requirements of reagents per nnit of treated oil may be very'materially -reduced. Furthermore, the treating agent obtai ned -by regenerating the lead sulfide:sludgez resirlts in a process of treating oils which has numerous advantages over the treatment of oils with fresh reagents m accordance' with present methods. For example, the treating m'edium obtained by regenerating'the:lead=sulfide sludge in accordance with this-inventionis capable of rapidly separating -from theoil treated therewith so that the :loss 0f oil by' entrainment is substantially eliminated and the period of settling materially reduced 7 thereby not'only saving oilbut'speedingup the operation and permitting a specifio'apparatus used in the treatmenttoba ndl'e a much larger volume of oil within a given time.

In general, the process of revivifyin'g-or regenerating the spent treating agent-orsul-V fidesludge resulting from the'litharge,'caustic and sulfur treatment of oil, that is the I doctor treatment, involves the agitationof such solution with its accompanying'caustic solution in the presence of air and-" fr'esh' litharge. The invention ma'y befullyl unders stood by reference to the following description of a typical case in which the :ini-tial 'ers"-of*sulfur, added to the mixture to -produce-as'weetproduct as evidenced by a negabulky mass to a dense powder-like materialv from which much of theoriginally treated oilpma'y be-skimmed leaving the sludgesuspended inla -solution of caustic.

"After the liberated oil has been removed from suspension of lead sulfide in the alkaline solution, fresh litharge may be added in the proportion-of about one pound of litharge per hundred gallonsof sludge and solution. This mixture is then blown with air, oxygen or oxygen containing gases for about ten to fifteen minutes after which it isready for use as an agent for furthertreating of petroleum distillates. The step of air blowing is essentialbut aswh'as beenstated above oxygen or, oxygen containing-gases maybe used instead of air and various oxidizing compounds such as patassium permanganate and the like may also be used.

A fresh batch ofpetroleum distillate requiring refining and sweetening treatment may then be'treated with the mixture prepared in theabovedescribed manner, ten to fifteenpercent'by volume of thismixture being added to the distillate' and intimately mixed'therewith. *Free sulfur in the proportionof'about one pound per five'hundred gal lonsof a petroleum distillate 'ofthe gasoline type is then-added to the oil'a'nd the entire mass. agitated until the desired product as evidencedby-a negative"doctor? test is ob-' tained. When therequired sweetness of prod uct is attained, the solution containing sulfide l with which I the treating solution separates from the-oil. r

' It is to be understoodthatthe proportions of ingredients.usedr willvary according to the character? of; the an treated-and the results required,ibut in any event-a material saving: is accomplished-over other processes" as indicated: by-t'he following res-u-lts obtained by- (A) 'treatin-g a particular gasoline "with tive, fdoctor test. -The spent solution con- "tainin'gthe sulfide sludge may then be drawn sodium plumbite solution followed by sulfur (customary doctor treatment) (B) treating the same type of gasoline with l 1 sulfide sludge air blown in the presence of the ingto the present invention described above.

ing value may become impaired, probably due Materials required-lbs. per bbl. (50-gals.) gasoline Material A B C Caustic"; 6. 41 4. 28 1. Lltharge 1. 05 0. 371 Sulfur 0. 278 0. 164

It is believed that the entire lead content of the original treating solution is recovered fromthesulfide sludge in reactive condition except for mechanical losses, however, it has been found after repeated treatments its treatto its being masked by accumulations of foreign matter. The spent lead sulfide may then be steamed, washed or filtered to restore its reactive power or it may be burned or otherwise treated to recover its valuable ingredients.

While a particular source of the lead sulfide sludge has been described, the invention may be applied to lead sulfide produced by the reaction of sodium sulfide and doctor solution or to other lead sulfides naturally or artifically produced.

Furthermore, the invention is not limited to a suspension of sulfide in caustic soda,

other alkalis such as potassium hydroxide,

soda ash and the like being suitable.

The invention may be broadly described as the production and use of a treating agent'for hydrocarbon oils, derived from the reaction of lead sulfide and litharge with oxygen in the presence of an alkali, and while no claim is made as to the exact chemical process involved, it is thought that the reaction is in accordance with the following equation PbS PbO -l- 20 GMOH 2M PbO M SO 3H O It is to be understood that the treating agent obtained in accordance with the hereinabove described process is preferably maintained ata proper alkaline strength of 10 to about 18 Baum equivalent. To maintain such alkalinity it may be desirable to add caustic, in solid or concentrated liquid form,

to the suspension. of lead sulfide either before, during or after the addition of litharge and either before, during or after agitation 1 with an oxygen containing gas.

I claim: '1. A method of refining oils comprising addinglitharge to a suspension of lead sulphide in an alkaline solution, oxidizing the of lead sulphide in alkaline solution, blowing 29 an oxygen containing gas through the mixture, adding the oxidized mixture to oil to be refined With agitation, then adding sulphur to said oil, and then separating the oil fromthe resulting suspension of lead sulphide in alkaline solution.

3. A method of refining hydro-carbon oils comprising adding litharge to a suspension of lead sulphide in caustic solution, oxidizing the mixture, adding the oxidized mixture to oil to be refined with agitation, then adding sulphur to said oil, and then separating the oil from the resulting suspension of lead sulphide in caustic solution.

4. A method of refining hydro-carbon oils comprising adding litharge to a suspension of lead sulphide in a caustic. solution, blowing an oxygen containing gas through the mixture, adding the oxidized mixture to oil to be refined, then adding sulphur to said oil, and then separating the oil from the resulting suspension of lead sulphide in caustic solution.

5. A method of refining petroleum distillates comprising adding litharge to a suspension of lead sulphide in an alkaline solution, blowing an oxygen containing gas through the mixture, adding the oxidized mixture to oil to be refined, then adding sulphur to said oil, and then separating the oil from the resulting suspension of lead sulphide in alkaline solution.

6. A method of refining petroleum distillates comprising adding litharge to a suspension of lead sulphide in a caustic solution, blowing an oxygen containing gas through the mixture, adding the oxidized mixture to oil to be refined, then adding sulphur to said oil, and then separating the oil from the resulting suspension of lead sulphide in a caustic solution.

7. A method of treating suspensions of lead sulphide in alkaline solution for use in refining oils comprising adding litharge to a suspension of lead sulphide in an alkaline solution, and then oxidizing the mixture.

8. A method of treating suspensions of lead sulphide in alkaline solution for use in refining oils comprising adding litharge to a suspension of lead sulphide in an alkaline solution, and then blowing an oxygen containing gas through the mixture.

9. A method of treating suspensions of lead sulphide. in alkaline solution for use in refining oils comprising adding: litharge to a suspension of lead sulphide in an alkaline solution in the proportions of about one pound to one hundred gallons of said suspension, and then blowing an oxygen containing gas through the mixture.

10. A methodof refining hydro-carbon oils which comprisesagitating oil with litharge in caustic solution and adding sulphur, separating the refined oil from the sulphide sludge thus produced,'adding litharge to the sludge, blowing an oxygen containing gas through the sludge, agitating fresh oil to be treated with the treated sludge and adding sulphur, and then separating the treated oil from the sulphide sludge thus produced.

11. A method of refining hydro-carbon oils comprising agitating the oil with litharge in caustic solution and adding sulphur, separating the treated oil from the sulphide sludge thus produced, allowing the sulphide sludge to settle, removing additional oil from the settled sludge, adding litharge to the sludge and blowing an oxygen containing gas through the mixture, agitating fresh oil with the treated sludge thus produced and adding sulphur, and then separating the treated oil from the sulphide sludge resulting from the last step. I

12. A treating agent for hydro-carbon oils derived from the reaction of lead sulphide,

litharge and oxygen in the presence of al-- kali and capable of producing a sludge readily separable by settling when mixed with an oil to be treated.

Signed at Colorado, Texas, this 26th day of November, 1928. v

' GEORGE HENRY BURRUSS; 

